Yes, more than likely. There are a number of problems that will occur. When the phone is picked up, the picture may go out. You may not get a picture at all. There may be a horizontal hold type problem with the picture. There is no telling what problem may be because of all the telephone manufacturers and the different types of telephones. If you have a 2.4GHz phone system or any other 2.4GHz system in your home or office, please consider using our hard-wired or 900MHz systems Line of Sight (LOS) means outdoors in clear, perfect conditions (no walls, trees, or any obstructions). This rarely happens in real life but this is how most receivers and transmitters are rated. All our receivers plug and play directly into your TV or VCR input jacks.